基于@ComponentScan注解的使用详解

基于@ComponentScan注解的使用详解,博智网带你了解详细信息。
目录

@ComponentScan注解的使用

一、注解定义
二、使用

1.环境准备
2.excludeFilters的使用
3.includeFilters的使用
4.自定义过滤规则

关于@ComponentScan注解的一些细节

@ComponentScan注解的使用
一、注解定义@ComponentScan注解的定义如下：
@Retention(RetentionPolicy.RUNTIME)@Target(ElementType.TYPE)@Documented@Repeatable(ComponentScans.class)public @interface ComponentScan {/*** 扫描路径* @ComponentScan(value = "https://www.yf-zs.com/redian/spring.annotation.componentscan")*/@AliasFor("basePackages")String[] value() default {};/*** 扫描路径*/@AliasFor("value")String[] basePackages() default {};/*** 指定扫描类* @ComponentScan(basePackageClasses = {BookDao.class, BookService.class})*/Class<?>[] basePackageClasses() default {};/*** 命名注册的Bean，可以自定义实现命名Bean，* 1、@ComponentScan(value = "https://www.yf-zs.com/redian/spring.annotation.componentscan",nameGenerator = MyBeanNameGenerator.class)* MyBeanNameGenerator.class 需要实现 BeanNameGenerator 接口，所有实现BeanNameGenerator 接口的实现类都会被调用* 2、使用 AnnotationConfigApplicationContext 的 setBeanNameGenerator方法注入一个BeanNameGenerator* BeanNameGenerator beanNameGenerator = (definition,registry)-> String.valueOf(new Random().nextInt(1000));* AnnotationConfigApplicationContext annotationConfigApplicationContext = new AnnotationConfigApplicationContext();* annotationConfigApplicationContext.setBeanNameGenerator(beanNameGenerator);* annotationConfigApplicationContext.register(MainConfig2.class);* annotationConfigApplicationContext.refresh();* 第一种方式只会重命名@ComponentScan扫描到的注解类* 第二种只有是初始化的注解类就会被重命名* 列如第一种方式不会重命名 @Configuration 注解的bean名称，而第二种就会重命名 @Configuration 注解的Bean名称*/Class<? extends BeanNameGenerator> nameGenerator() default BeanNameGenerator.class;/*** 用于解析@Scope注解，可通过 AnnotationConfigApplicationContext 的 setScopeMetadataResolver 方法重新设定处理类* ScopeMetadataResolver scopeMetadataResolver = definition -> new ScopeMetadata();这里只是new了一个对象作为演示，没有做实际的逻辑操作* AnnotationConfigApplicationContext annotationConfigApplicationContext = new AnnotationConfigApplicationContext();* annotationConfigApplicationContext.setScopeMetadataResolver(scopeMetadataResolver);* annotationConfigApplicationContext.register(MainConfig2.class);* annotationConfigApplicationContext.refresh();* 也可以通过@ComponentScan 的 scopeResolver 属性设置*@ComponentScan(value = "https://www.yf-zs.com/redian/spring.annotation.componentscan",scopeResolver = MyAnnotationScopeMetadataResolver.class)*/Class<? extends ScopeMetadataResolver> scopeResolver() default AnnotationScopeMetadataResolver.class;/*** 用来设置类的代理模式*/ScopedProxyMode scopedProxy() default ScopedProxyMode.DEFAULT;/*** 扫描路径如 resourcePattern = "**/*.class"* 使用includeFilters 和 excludeFilters 会更灵活*/String resourcePattern() default ClassPathScanningCandidateComponentProvider.DEFAULT_RESOURCE_PATTERN;/*** 指示是否应启用对带有{@code @Component}，{@ code @Repository}，* {@ code @Service}或{@code @Controller}注释的类的自动检测。*/boolean useDefaultFilters() default true;/*** 对被扫描的包或类进行过滤，若符合条件，不论组件上是否有注解，Bean对象都将被创建* @ComponentScan(value = "https://www.yf-zs.com/redian/spring.annotation.componentscan",includeFilters = {*@ComponentScan.Filter(type = FilterType.ANNOTATION, classes = {Controller.class, Service.class}),*@ComponentScan.Filter(type = FilterType.ASSIGNABLE_TYPE, classes = {SchoolDao.class}),*@ComponentScan.Filter(type = FilterType.CUSTOM, classes = {MyTypeFilter.class}),*@ComponentScan.Filter(type = FilterType.ASPECTJ, pattern = "spring.annotation..*"),*@ComponentScan.Filter(type = FilterType.REGEX, pattern = "^[A-Za-z.]+Dao$")* },useDefaultFilters = false)* useDefaultFilters 必须设为 false*/Filter[] includeFilters() default {};/*** 指定哪些类型不适合进行组件扫描。* 用法同 includeFilters 一样*/Filter[] excludeFilters() default {};/*** 指定是否应注册扫描的Bean以进行延迟初始化。* @ComponentScan(value = "https://www.yf-zs.com/redian/spring.annotation.componentscan",lazyInit = true)*/boolean lazyInit() default false;/*** 用于 includeFilters 或 excludeFilters 的类型筛选器*/@Retention(RetentionPolicy.RUNTIME)@Target({})@interface Filter {/*** 要使用的过滤器类型，默认为 ANNOTATION 注解类型* @ComponentScan.Filter(type = FilterType.ANNOTATION, classes = {Controller.class, Service.class})*/FilterType type() default FilterType.ANNOTATION;/*** 过滤器的参数，参数必须为class数组，单个参数可以不加大括号* 只能用于 ANNOTATION 、ASSIGNABLE_TYPE 、CUSTOM 这三个类型* @ComponentScan.Filter(type = FilterType.ANNOTATION, value = https://www.yf-zs.com/redian/{Controller.class, Service.class})* @ComponentScan.Filter(type = FilterType.ASSIGNABLE_TYPE, classes = {SchoolDao.class})* @ComponentScan.Filter(type = FilterType.CUSTOM, classes = {MyTypeFilter.class})*/@AliasFor("classes")Class<?>[] value() default {};/*** 作用同上面的 value 相同* ANNOTATION 参数为注解类，如Controller.class, Service.class, Repository.class* ASSIGNABLE_TYPE 参数为类，如 SchoolDao.class* CUSTOM参数为实现 TypeFilter 接口的类，如 MyTypeFilter.class* MyTypeFilter 同时还能实现 EnvironmentAware，BeanFactoryAware，BeanClassLoaderAware，ResourceLoaderAware* 这四个接口* EnvironmentAware* 此方法用来接收 Environment 数据，主要为程序的运行环境，Environment 接口继承自 PropertyResolver 接口，* 详细内容在下方* @Override* public void setEnvironment(Environment environment) {*String property = environment.getProperty("os.name");* }** BeanFactoryAware* BeanFactory Bean容器的根接口，用于操作容器，如获取bean的别名、类型、实例、是否单例的数据* @Override* public void setBeanFactory(BeanFactory beanFactory) throws BeansException {*Object bean = beanFactory.getBean("BeanName")* }** BeanClassLoaderAware* ClassLoader 是类加载器，在此方法里只能获取资源和设置加载器状态* @Override* public void setBeanClassLoader(ClassLoader classLoader) {*ClassLoader parent = classLoader.getParent();* }** ResourceLoaderAware* ResourceLoader 用于获取类加载器和根据路径获取资源* public void setResourceLoader(ResourceLoader resourceLoader) {*ClassLoader classLoader = resourceLoader.getClassLoader();* }*/@AliasFor("value")Class<?>[] classes() default {};/*** 这个参数是 classes 或 value 的替代参数，主要用于 ASPECTJ 类型和REGEX 类型* ASPECTJ为 ASPECTJ 表达式* @ComponentScan.Filter(type = FilterType.ASPECTJ, pattern = "spring.annotation..*")* REGEX参数为正则表达式* @ComponentScan.Filter(type = FilterType.REGEX, pattern = "^[A-Za-z.]+Dao$")*/String[] pattern() default {};}}